The operation of such a kind of machines, arranged and working between the folding system and the packaging system, is very complex due to the nature of the material normally used (highly pliable tissue paper), and above all to the high working speed that is imposed.
These machines or apparatus have substantially the features described e.g. in European Patent EP537125, in the name of the same present applicant. They comprise belt or chain conveyor systems that feed single folded article from the outlet of the folding machines towards an accumulation and counting unit having the function of grouping the articles in stacks, each including a pre-settable number of pieces, controllable as needed. The accumulation and counting unit comprises a series of adjacent and mutually spaced collecting discs (variable in number depending on the size of the machine, revolving in a mutually integral fashion and provided with pockets, for collecting single folded products, the pockets being in the shape of curvilinear tangential laminations, adjacent to one another and partially superimposed, in such a way that each pocket, indeed defined by the spacing between to consecutive laminations, is adapted to house a single folded article.
The collecting discs cooperate tangentially with separating wheels revolving in a step-by-step fashion, having radially projecting blades, suitably spaced along the periphery of the wheel so that; between two consecutive ranks of adjacent blades (each rank being determined by a plurality of coplanar blades, each on a respective wheel), a housing is formed in which a group or stack of articles is accumulated. Such articles are taken by the blades from the collecting discs, following to insertion of the same blades in the space between a disc and an adjacent one.
Downstream of the accumulation and separating wheels, transportation means are adapted to withdraw the accumulated groups of articles and to convey them towards the packaging system. The transportation means, according to the known art, can adopt different arrangements, such as chain or slider arrangements.
As mentioned, the problems affecting the known apparatus essentially result from the difficulty of ensuring reliable performances in high-speed operation, as imposed by more and more demanding productive requirements. In this respect, the flexibility, speed and reliability of the known solutions are not fully satisfactory, and indeed are often the cause of production stops, in turn causing wastes of material and malfunctions of the packaging machines.
There is therefore a strong need for an integrated system for the accumulation, counting and transportation of the product from the folding machine, which is flexible, reliable, highly productive and with no restraining limits in the working speed.